cython-mode.el: add missing grouping to keyword regexps

* fix font-locking of keyword regexps (matcher was referring to group
  that ceased to exist after 0a7e8d60)

* fix adding customized font-lock-keywords

  Old code behaved bad because it changed an element of a list that was
  compiled into "python-mode" function definition.  This had an
  unfortunate side effect of propagating cython-specific keywords into
  vanilla python buffers.

* fontify new types in ctypedef statements

* add more keywords ("cppclass", "new", "del", etc.)

* add more builtin types ("Py_UNICODE", "ptrdiff_t", etc.)

* fix font-locking of "except?"

* fontify types with font-lock-type-face, not py-class-name-face

Conflicts:
	CHANGES.rst

--HG--
extra : amend_source : 8230801cb0e5cff944c0a7b4cbd0718f28cb344e

--HG--
extra : amend_source : 44298a4bc8ecb8fcc729f7b741ecedd6ad4200b3

document specialisation behaviour when a fused memory-view type occurs multiple times in a function signature

work around bug in fused types code that prevents typing the signature of the runtime dispatch function

fix test: runtime dispatch is done only on the first occurrence of a fused buffer type and later mismatches lead to type failures after the call (which is acceptable since it speeds up the dispatch and leads to an error anyway)

fix creation order of set literals by first generating all items and only then adding them to the set (as CPython does it)

--HG--
rename : tests/run/set.pyx => tests/run/set_literals.py

fused types: specialize each base type only once, also for compound type args